Hone to size .940

[Boot]

How much undersize should a bore of .940 be before honing?

 

[rklopp]

Assuming said bore is reasonably straight, round, parallel, and has decent surface finish, I'd say the start point for honing should be 0.937 to 0.939. With coarse enough grit, you can take off a couple of mils in reasonable time (minutes).

 

[Boot]

Thanks rk. It's in aluminum and I sort of figured that would be the amount. Hopefully I can do it. I have a .002 taper in the bore right now in a length of about 4". We had honing machines where I had worked before retirement, but I never had anything to do with them and didn't know what they left in the bores for final finish. I worked on large CNC - VTL's and didn't do anything as small as they were working on. I'm making a small Super Stirling engine bore of .940 . I'll have to buy a small hone to do the job. Most likely one used on brake cylinders.

 

[b.lindsey]

Just remember to use a telescoping gage and micrometer to measure the bore. Calipers won't give you a true reading on an ID.

Bill

 

[jpeter]

The standard brake cylinder hone won't hone out a taper. A Sunnen hone will. The home shop guy will probably have to lap out a .002 taper or take it to a job shop to hone it out .002.

 

[Boot]

Thanks for the info. gentlemen. I am using telescopic gages and a 1" mic. to check it. I'll have to work on getting the taper out of it. I'll try to put a indicator on the tool and tap it out .001 in very slight increments as the bore is finished. To bad the company went North to Canada that I worked for. I would of had my buddies hone it out straight on the Sunnen we had in the shop. That was 10 years ago. Time moves on. I miss that shop all the time. It was a good company to work for.
Merry Christmas to all. Boot